Adaptive response, evidence of cross-resistance and its potential clinical use.

Milisav I, Poljsak B, Suput D - Int J Mol Sci (2012)

Bottom Line:
Stress responses are mechanisms used by organisms to adapt to and overcome stress stimuli.Studies have reported life-prolonging effects of a wide variety of so-called stressors, such as oxidants, heat shock, some phytochemicals, ischemia, exercise and dietary energy restriction, hypergravity, etc.These stress responses, which result in enhanced defense and repair and even cross-resistance against multiple stressors, may have clinical use and will be discussed, while the emphasis will be on the effects/cross-effects of oxidants.

ABSTRACTOrganisms and their cells are constantly exposed to environmental fluctuations. Among them are stressors, which can induce macromolecular damage that exceeds a set threshold, independent of the underlying cause. Stress responses are mechanisms used by organisms to adapt to and overcome stress stimuli. Different stressors or different intensities of stress trigger different cellular responses, namely induce cell repair mechanisms, induce cell responses that result in temporary adaptation to some stressors, induce autophagy or trigger cell death. Studies have reported life-prolonging effects of a wide variety of so-called stressors, such as oxidants, heat shock, some phytochemicals, ischemia, exercise and dietary energy restriction, hypergravity, etc. These stress responses, which result in enhanced defense and repair and even cross-resistance against multiple stressors, may have clinical use and will be discussed, while the emphasis will be on the effects/cross-effects of oxidants.

f4-ijms-13-10771: Antioxidant defenses. Antioxidant defenses can prevent the generation of reactive oxygen species (ROS) and intercept free radicals [95]. There are enzymatic defenses and non-enzymatic defense systems that protect the cells against free radicals and ROS [4]. The formation of some ROS is inevitable during normal metabolism and is necessary also for normal cell function.

Mentions:
The protective molecules include antioxidant enzymes, like superoxide dismutase (SOD), glutathione peroxidases, catalase, molecules like glutathione and the compounds derived from diet, like ascorbate, etc. (Figure 4). Regarding their function, the antioxidant defences can be divided into (1) enzymes that catalytically remove reactive oxygen species, like SOD, superoxide reductase, catalase and peroxidase; (2) agents that decrease the formation of reactive oxygen species by minimizing the availability of pro-oxidants, like iron and copper ions or heme. Such are transferrins, albumin, heme oxigenases, metallothionein, etc.; (3) proteins protecting biomolecules against oxidative damage, like chaperones; (4) physical quenchers, for example of a singlet oxygen by carotenoids; (5) agents that are preferentially oxidized, like glutathione, α-tocopherol, bilirubin, ascorbate, urate, albumin, etc. [93,94].

f4-ijms-13-10771: Antioxidant defenses. Antioxidant defenses can prevent the generation of reactive oxygen species (ROS) and intercept free radicals [95]. There are enzymatic defenses and non-enzymatic defense systems that protect the cells against free radicals and ROS [4]. The formation of some ROS is inevitable during normal metabolism and is necessary also for normal cell function.

Mentions:
The protective molecules include antioxidant enzymes, like superoxide dismutase (SOD), glutathione peroxidases, catalase, molecules like glutathione and the compounds derived from diet, like ascorbate, etc. (Figure 4). Regarding their function, the antioxidant defences can be divided into (1) enzymes that catalytically remove reactive oxygen species, like SOD, superoxide reductase, catalase and peroxidase; (2) agents that decrease the formation of reactive oxygen species by minimizing the availability of pro-oxidants, like iron and copper ions or heme. Such are transferrins, albumin, heme oxigenases, metallothionein, etc.; (3) proteins protecting biomolecules against oxidative damage, like chaperones; (4) physical quenchers, for example of a singlet oxygen by carotenoids; (5) agents that are preferentially oxidized, like glutathione, α-tocopherol, bilirubin, ascorbate, urate, albumin, etc. [93,94].

Bottom Line:
Stress responses are mechanisms used by organisms to adapt to and overcome stress stimuli.Studies have reported life-prolonging effects of a wide variety of so-called stressors, such as oxidants, heat shock, some phytochemicals, ischemia, exercise and dietary energy restriction, hypergravity, etc.These stress responses, which result in enhanced defense and repair and even cross-resistance against multiple stressors, may have clinical use and will be discussed, while the emphasis will be on the effects/cross-effects of oxidants.

ABSTRACTOrganisms and their cells are constantly exposed to environmental fluctuations. Among them are stressors, which can induce macromolecular damage that exceeds a set threshold, independent of the underlying cause. Stress responses are mechanisms used by organisms to adapt to and overcome stress stimuli. Different stressors or different intensities of stress trigger different cellular responses, namely induce cell repair mechanisms, induce cell responses that result in temporary adaptation to some stressors, induce autophagy or trigger cell death. Studies have reported life-prolonging effects of a wide variety of so-called stressors, such as oxidants, heat shock, some phytochemicals, ischemia, exercise and dietary energy restriction, hypergravity, etc. These stress responses, which result in enhanced defense and repair and even cross-resistance against multiple stressors, may have clinical use and will be discussed, while the emphasis will be on the effects/cross-effects of oxidants.